


Perfect form and functionality

by ShadeDuelist



Series: Shade in Undertail: The Undertale Sinful Timelines Collection [2]
Category: Undertale (Video Game)
Genre: Alternate Universe - Underswap, Ectoplasm, Gen, Mettaton EX, Roughness, Self-cest, Soul Sex, mettacest - Freeform, papyton
Language: English
Status: Completed
Published: 2016-02-26
Updated: 2016-03-05
Packaged: 2018-05-23 10:11:57
Rating: Mature
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 8,065
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6113281
Author URL: https://archiveofourown.org/users/ShadeDuelist/pseuds/ShadeDuelist
Summary: <blockquote class="userstuff">
              <p>(based on an idea hotlegmeme gave me - by the way, thanks for the brainwave :D)</p><p>Underswap AU - Mettablook gets a HUGE gift from doctor Undyne: a robotic body just like Napstaton's!  They've always envied their cousin's handsome form, and now they get one for themself, so who can blame them for being overwhelmed?  ...But while checking their new body out, they stumble upon some features that get them just a little flustered, and then they start thinking how well those would work out.  So they decide to test them out the only way available...</p><p>Later, after they meet and fall in love with Papyrus, Mettablook ends up confessing his dirty little secret and Papyrus wants a demonstration...</p>
            </blockquote>





	1. Test ride

“M-metta?  Mettablook?”  The discreet knock on the ghost’s door made them look up from their bed, on which they’d been laying to write in yet another diary.  The voice sounded like doctor Undyne, their neighbor, who occupied the large Waterfalls Laboratory that used to belong to docter Rivers, but… but that couldn’t be the case, right?  Doctor Undyne was the Royal Scientist, always busy with something-or-other for Queen Toriel - so busy for the Queen, in fact, that she hardly ever exited her home.  Mettablook could sometimes hear her crying, and they thought that maybe she was just as alone as they were…  “M-mettablook, a-are you in there?”  This time, the knock was a bit louder and the voice of the doctor was unmistakeable; Mettablook blinked and got up from their bed, drifting over to the door in surprise.  What could the doctor’s reason for coming over be?  As far as they were aware of, Mettablook was one of the least interesting monsters in the entire underground.  In fact, the only thing that made them even _remotely_ interesting was the fact that their cousin was the UnderJam radio station’s famous DJ Napstaton.

“W-wait… I’m here, l-let me… open the door for you…”, Mettablook stammered, floating over to the doorway and opening it, finding the white lab coat-wearing woman standing on their doorstep, looking utterly nervous.  “...D-doctor Undyne, what… brings you t-to my home?”, the ghost asked carefully, and the woman bit her lip subconsciously before answering.

“W-well, uh… Can I… come inside?  Please?”, Undyne asked, looking behind her, making Mettablook more and more worried.

“U-undyne, i-is s-something the matter?  I… I-if you need help, I ca-can’t offer much…  I-I’m not strong, l-like the R-royal guard…  M-maybe you’d b-be better asking A-alphys for he-help-“, they tried, only for the doctor to shake her head and laugh softly, relaxing a little.

“No, Mettablook, t-that’s okay!  I… a-actually, I… someone t-told me recently t-that I’m a h-ho-horrible neighbor t-to you…  I m-mean, my… uh, my experiments… m-must keep you awake at all, uh, hours o-of the night… and… well, y-your cousin… I did s-so m-much for them, and n-nothing at all for y-you…”  That, if anything, made Mettablook blush deeply.  If they were completely honest, they had often thought it unfair that Napsta had gotten their big break due to their friendship with the doctor before she’d become Royal Scientist… but only in their bad moments, though, and Mettablook would rather turn to glittery dust and get scattered by the wind before they’d want Napstaton to lose even a _second_ of their fame because of them.  And it was that last thought that made them answer quickly and vehemently.

“O-oh n-n-no, doctor U-undyne!  N-na-napsta _w-wanted_ that body s-so badly… t-they wanted a b-body to reflect t-their… passion f-for music…  I… a-all you did was give… give t-them that…”

“I’m not saying I… h-heh, I d-didn’t shoehorn him i-into the UnderJam radio s-station, he… a-applied for the job a-and everything…”, Undyne defended herself, though she blushed guiltily while speaking, and Mettablook raised a ghostly eyebrow despite their shyness.  “...o-oh, okay, yeah, I _did_ shoehorn him into UnderJam, b-but…!”

“I d-didn’t mean…  D-doctor, I’m _ha-happy_ f-for Blookie!  N-not jealous at all!!”  Mettablook looked at the doctor semi-desperately, seeing her look back in surprise before she sighed, prompting the small pastel-pink ghost to do the same and speak up again.  “...S-so you… w-wanted to do something f-fo-for m-me...?”

“Y-yeah!  I mean, Napstablook and I… w-we were really good friends before… before all of this happened.  I g-gave t-them their body b-because th-they were really upset b-by not being able t-to… well… not being able to p-put _all_ of their passion in their music…”

“Y-yeah, I know…”, Mettablook spoke softly.  Their cousin had been genuinely upset about that, to the point of even having often admitted they felt like garbage for wanting a way to put even _more_ commitment and dedication into his deejaying but at the same time feeling like that would disappoint them for not feeling content with what they had, like Mettablook did.  “...S-still…!  N-napsta… _Blookie…_  T-they deserve a break t-this big!  N-napstaton’s m-music is… _powerful_ …  H-hu-hundreds of m-monsters get insp-inspired by him e-e-everyday!!  H-he wo-wouldn’t have b-been able to d-do that if he was… s-still just a gh-ghost...”

“Well…  I, uh… felt horrible f-for not… for a-all of the… trouble?  I caused, kinda?  You know?  ...T-taking your cousin away from you…  a-and l-leaving you h-here, all alone…  S-so!”, the ichthyan monster said determinedly, though not without her usual innate shyness, which now fuelled the light blush over her blue cheeks, turning them an interesting shade of purple.  “...So… I, uh, a-asked Napstaton… I mean, I asked _Napstablook_ a-about what’d m-make you happy… and… w-well, I…”  Suddenly, before Mettablook could protest or turn themself transparent and insubstantial, doctor Undyne grabbed their ghostly hand and pulled them along out of their house, closing the door with her free hand before gently pulling them along to her lab.  In there, on one of the workbenches, lay a lumpy form under a thick sheet, but Mettablook was beyond noticing that at the time, turning instead to the scientist.

“D-do-doctor U-undyne, p-please, w-warn me next ti-time... before y-you pull m-me off… l-like that…!”

“I’m sorry, M-mettablook, but… I… I wanted to s-show you w-what I made for you!”  With a flourish - something that the doctor maybe had their cousin to thank for, Mettaton caught themself thinking - the doctor removed the sheet, and underneath it…  “...So, uh… d-do you like it?”  Mettablook could see the fish-like monster bite her lips with her sharp teeth, showing how highly nervous she was, but that barely made it through the haze that lay over their senses.  In front of them lay a body similar to Napstablook’s - no, _Napstaton’s_ , because their cousin had chosen to fuse their soul with the body, Mettablook amended.  All of it looked bland, though: pale chrome and light metal were the predominant materials, and the little pink ghost could guess the reason for that even before the doctor voiced it, bringing tears to their eyes.  “...O-of course, it isn’t much t-to look at yet, but… well, I c-can customize it t-to your specs, l-like Napstaton g-got!”

“...oh… o-oh, my…  oh my _w-word…_ !”, Mettablook softly whispered, circling the body.  Slender limbs, a delicate but handsome face… handsome features that were masculine, but not _too_ masculine…  There was no denying that they could see themselves inhabiting this body, using it much like Napstablook used his… though fusing with it like their cousin had seemed a little too far.  Still, Mettablook couldn’t deny that the gift was _lavish_ and _perfect_ , and they suddenly felt undeserving.  “D-doctor Undyne…  W-why…?  W-what…?  A-all you did f-for Napsta… a-all you did for him, a-and you still… you still h-have thi-this to give t-to m-m-me?”

“Yes!  I… Napstaton h-helped.  A _l-lot_ , actually.  He… k-kinda held a fundraiser?  And h-he told me w-what you… w-wanted?  L-like, how m-much you liked t-the humans o-on the television, and… a-and how much y-you want to b-be a television s-star just li-like them…  And he, uh, _k-kinda_ told me about h-how you’d like a _m-ma-male_ body, t-too…”  Mettablook’s cheeks turned a violent pink, they could tell, but before they had the chance to stammer out a flustered reply, the scientist beat them to it.  “I m-mean… I know h-how ghosts d-don’t really h-ha-have a gender?  N-napstablook s-said he w-wanted a m-m-male body a-as well j-just l-like you w-wanted… but f-for him, it’s because… w-well, because i-it’s _easier_ … a-and b-beca-because h-he l-liked the m-more… more _a-angular_ designs…”  A thousand questions at once now flooded Mettablook’s mind - did this body have the rectangular shape like Napstaton’s first form, too?  How would the battery life be?  What about their soul?  Would their soul need to be ‘hooked up’ to the body proper?  Would the process of first inhabiting the body be painful?  Could they still use their ghostly attacks in case of an emergency? - but the doctor once again beat him to it.  “I k-know you have a w-whole lot of questions… a-and I promise I’ll a-answer them all!  F-fuh huh… w-we don’t want y-you to, uh, g-go in u-unprepared…  Now, uh, I know… o-or, I _think_ I know, at least, w-what your first question is… a-and I’m ha-happy to say t-that the batteries a-are _much b-better_ n-now!  I’ve w-worked out a better f-fuel…  S-so, uh, w-what other questions d-do you have?”

“Well, just… j-just so many…  B-but I’m feeling… a li-little bit o-overwhelmed, t-to tell you the truth, d-doctor…  C-could I maybe… u-uh… g-get my bearings a l-li-little… o-on my own…?”, Mettablook asked shyly, prompting a soft blush and a firm nod from the fish-like scientist.

“O-of course!  I, uh… I’m due a-at the castle anyways, f-for my, uh, weekly meeting w-with Queen Toriel… S-so!  Uh!  ...Y-yeah, just… t-try it out, I’d say?”

“Oh!  I c-can just… uh… i-inhabit t-this body l-like… like M-mad inhabited t-that dummy b-back when w-we were younger?”, the little ghost queried, and this time doctor Undyne answered with a more confident grin.

“Y-yeah, totally!  I-it’s just, uh, y-you need to move y-your soul i-into the body, a-and then you can con-control it!  J-just like that dummy, yeah!  ...I-if you want to, uh, _f-feel_ what the body feels a-and such, though, y-you’d have to… y-your soul w-would n-need to be, uh, _hooked up_ t-to the sensor feeds, l-like Napstaton’s s-soul is…”

“Oh!  W-well, n-not just yet…”, Mettablook said with a soft smile, nodding.  “I’ll, uh, t-try it on f-for size… a-and doctor Undyne?”, they spoke softly when the scientist was already at the door to the lab, prompting her to turn around and look at the ghost with a questioning look that made Mettablook’s cheeks feel just a little warmer as they spoke on: “...I-I’d l-like to help you… w-with the cu-customizations… i-if that’s… okay, I m-mean…”

“I’d like that!”, the woman said, nodding softly before walking out of the lab, leaving Mettablook with the body that they admittedly already considered their own after seeing it and knowing it was made especially for them.  Smiling, Mettablook floated over the body, looking it over.  The expression was a bit blank, but with a small glimmer of magic, they easily molded the shape of the face into a smile to match theirs.

“H-hey, there, ha-handsome…”, the ghost tried shyly, giggling when the robot body mimicked the movement of their ghostly lips to form the same sentence - they had forgotten to relinquish their hold on their magic, which caused the face to still correspond to their features.  It felt… so easy, and natural…  Mid-giggle, they let go of their hold on the magic they’d used for that purpose, causing the face of their future robot form to freeze in an expression of gentle amusement, with eyes closed and a broad open-mouthed smile.  “O-oh… tha-that w-was fun…”, they admitted, a small glitter on the robot’s features reflecting their soft blush.  “...A-and you _are_ handsome…  I m-mean, _I_ am ha-handsome...”, Mettablook amended, using their moment of soul-fluttering embarrassment to further look the robot over.  The ridiculously over-the-top shoulderpads that Napstaton had gained so many admirers with were absent from his form, instead being replaced with a much rounder, more subdued version of them, giving the robotic form broad shoulders but without the overly contrived feel.  There was a touchscreen dial and a speaker on the chestpiece, probably to change the quality of their voice - _his_ voice, Mettablook again amended, this time with a happy trill in their soul - at a moment’s notice.  Not that they would _need_ that, but it was handy nonetheless.  The soul container, then: it wasn’t situated in the chest area, like Napstaton’s, but at the waist, but still it held the same wires ending in circular pads as Napstaton’s soul container did.  Those would probably be the sensor pads that doctor Undyne had meant, Mettablook mused, touching one and then, at the same time, touching the body’s arm.  The ghost could feel a soft, distant sensation like being touched - but more overwhelmingly, they could feel that sense of _solidity_ , and that got their eyes to go wide and nod.  Maybe… maybe that kind of… almost-corporeality… wasn’t as bad as they’d thought it would be?  It felt… nice… to be solid and sturdy… to not have someone’s hand sink through when they touched them…

To maybe, just maybe… be able to _kiss someone_ and feel them press against them without having to worry about keeping their magic focused…

Realizing they were getting flustered by that thought, Mettablook shook their ghostly head and continued their inspection of their new future body - because if there was one thing they were utterly certain of, it was the fact that they would inhabit this new body, with all its shiny functionality and handsome features, as soon as Undyne had it customized.  The legs… all sleek and shiny, with barely a ridge to show where the welds were; as Mettablook touched them, they found the metal bend slightly under their half-corporeal touch and they smiled.  It felt like silicone under their hands!  It would feel just like a real human would, they were sure!

“...W-well, humans would f-feel this… soft, a-and supple, and w-warm to the touch…”, the pastel-pink ghost admitted, picturing one of their favorite humans from one of doctor Undyne’s videos and the way they imagined that human’s legs would feel like.  They’d always looked so… pink, and perfect!  “...oh… mmm…”  Mettablook only realized they were a little flustered by the feel of their future legs when they caught themself petting the silky, fleshy expanse of them, which reflected the soft glow of their soul back at them.  Startled, they tried to quell the glow within themself with a soft and slightly embarrassed mutter: “O-oh… my… I s-shouldn’t…”  Pulling their ghostly hand away, they couldn’t help but brush it over the length of the robotic body’s thigh, prolonging the sensation as long as they could, and then-  “ _O-oh my g-god!_ ”  Their ghostly hand apparently had managed to pry loose a part of the robot, because the metal plate at the groin came undone, and the shy little ghost squeezed their eyes shut as it hit the floor of the lab with a dull ‘thud’. However, after Mettablook’s initial fear of having ruined their new body before they’d even come to take full possession of it, they looked the damage over and realized, mainly by the amount of workmanship put into the parts underneath, that it was not ruined or broken after all.  But the worry of having broken something quickly turned into the embarrassment of realizing just how _life-like_ the body had been made.

Mettablook’s collection of film included only musicals, but that didn’t mean that they were a stranger to human anatomy, not by a long shot.  They had once been awakened by loud incomprehensible moans coming from doctor Undyne’s house in the middle of the night, and when they’d checked through the window to make sure that the ichthyan scientist was okay, they’d instantly noticed that it was just one of the doctor’s animes playing at slightly louder-than-needed volume - and the images it had shown… humans had very _interesting_ anatomy, Mettablook had concluded.  For one, their male and female versions had… compatible anatomy instead of souls that breached the expanses of their bodies to squish together with their partner’s soul or solidified magic, which was what monsters had gotten.  And the way humans seemed to enjoy being touched and… stimulated…  Especially the male humans: they, like Mettablook, seemed to climax _very messily_ , and that had led the ghost to believe that, if they ever would attain a human form, they’d be male.  And now, doctor Undyne had apparently granted them their wish better than they’d dared think of!

“O-oh… I s-shouldn’t… t-think about that…!”, Mettablook said, though they had to admit that the robotic equivalent of human male genitals certainly looked intriguing.  Tentatively, they reached out a ghostly hand and touched it, feeling the same silky, silicone-like texture as the legs had had, only… somehow softer, and more delicate.  “...I-it feels… so ni-nice…”, Mettablook admitted, their soul now glowing fiercely enough to illuminate the workbench, the pink hue lending an alluringly warming effect to the body that they would soon make their own.  Oh, how wonderful would it be to inhabit this body, with its verisimilitude of an actual human male!  How handsome they’d look - no, how handsome _he_ ’d look!  And… and how spectacular it would be to derive pleasure, too…  Mettablook couldn’t deny that they weren’t thinking about these extra additions doctor Undyne made and how useful they’d be.  Monsters maybe lacked the physicality humans had, but that didn’t mean they didn’t have _some_ measure of firmness.  Even they, themself, would be able to…

...able to…

With a groan, Mettablook caught their thoughts about what it would feel like to have sex the way humans did, only with _themself_ as the other party, and they shook their head.

“T-this is n-not… I m-mean, it’s m-my body, but… I can’t d-do t-that to _m-myself_ …”, they said softly, breathily, but the still-functioning part of their mind told them that wasn’t entirely true, that it even made an odd kind of sense to test _every_ function of their new body out on themself first before subjecting other monsters to it.  “...I s-sho-shouldn’t…”, they amended, eyeing the circular pads, but then gently reaching out to grasp them.  A touch of their new body’s robotic dick with one ghostly hand while holding the sensor pads in the other had a vaguely scintillating effect on their soul, and Mettablook found themself sighing happily.  “M-mh…  I-it feels… g-good, though… ohh…  W-would it r-really be… a bad thing… t-to test h-how it’d feel…?”, they asked themself, reaching inside of their ghostly body with the pads and putting them gently onto their soul before touching the robotic member again.  And when they did…  “ _Mh- mmmmhh…!_ ”  It was like the faintest, lightest kind of caress to their soul, both heated and teasing at the same time, and glittering sparkles shot out of Mettablook’s body helplessly at the pleasure.  “O-oh… w-well, that’s… T-that’s so… g-good…”, they whimpered to themself, shuddering as they slowly stroked their new body’s dick.  The feedback was almost instantaneous and, if Mettablook’s ghost-body had any toes, they would’ve curled with the constant stimulation of the sensor pads on their soul.  It felt _amazing_ , better than they could have ever imagined!  And the more they got excited, the more their body solidified to make the touches more ‘fleshed out’, so to speak, so the more they got back from it.  Groans soon filled the empty lab - Mettablook knew Undyne was by now long gone, and not many monsters dared venture near the lab anyway, so they didn’t need to hold back any.  “Oh… ohhh y-yes… yessss…”, they pleaded with no one in particular, now actually making fierce jerking motions with their ghostly pink hand tightly shut around the metal dick, absorbed in the near-constant flow of feedback.  However, they still found themself wondering what it would be like to have their future member _inside_ of another monster, and seeing as they themself were the ideal monster to test it out since they could work out how it felt for _both_ parties that way…  “ _Nnnh!_ ”, the little ghost groaned, floating upward and then slowly settling their now semi-solid body on top of their empty future body, embedding the tip of its robotic dick ever-so-carefully inside themself.

Instantly, their entire body shook.  It had always felt good to press _anything_ into the lower half of their body when they were aroused - mostly whatever had been conveniently at hand, though - but this?  Not only did they feel the pleasure they usually derived from it, but now, with their robotic body wired up to their soul somewhat, they also got to feel the pleasure of pressing into themself and to experience the tight, almost constricting hold their body had on the invading member.  If it had been good before, just touching their future self, now it felt _divine_ , and their magic started glowing bright enough to illuminate the entire lab in rapidly changing hues of pink, pulsing rapidly as a tell of their heightening arousal.

“ _O-ooooh… oh m-my good…n-ness…  Ahh… a-ah-ahh…_ ”  Mettablook could do nothing apart from groan inarticulately as they sank down onto the cool metal appendage, which warmed surprisingly quickly to their ghostly body’s tight hold.  Each fraction of an inch deeper they allowed themself to sink made them whimper more loudly.  It was shameful and wrong and they were _loving every second of it_ .  “ _I… o-oh, t-this… ahhh…!  M-mmh…  t-too good… s-soooo… t-tiiight…_ ”  Dignity was a thing of the past as the ghost eagerly floated up a little again only to sink deeper fast, taking the metal dick deeper into their semi-transparent, glittering body, which was now liberally dripping at the bottom, liquid running over their future body and evaporating more and more slowly, leaving hot pink trails all over the metal.  Their motions grew rough, even, and soon the sound of the robotic body’s joints creaking provided a counterbalance to their moans and sighs and gasps.  But Mettablook could care less that they were putting strain on the body.  This was a test, so shouldn’t they see if the metal could take his excitement?  Shouldn’t they be able to get carried away in their new body?  Shouldn’t they be _allowed_ to ride their way to a high unlike anything they’d felt before?  “ _Uhh… t-too good, t-too tight… o-oh, yes… y-yesss… ohh…_ ”  Mettablook was skating the edge already - or did it just _feel_ like they were racing to the finish line in record time, they wondered in a split second in between gasps - but they were past caring about the fact that the entire workbench creaked precariously, or that their magic was running so high that the robotic body mimicked their blissful expression… all they felt, all they could still register, was the double pleasure of filling and being filled, the twinned and twining joy of the tight, breathtakingly perfect squeeze that they were both on the giving and the receiving end of.  “ _Ohh, y-yes-yessss-Y-Y-YEEEEEEESSSSSS…!!!_ ”  With a loud cry, Mettablook lost it: ectoplasm splashed _everywhere_ , coating the body beneath their ghostly form with a thick layer of glittering fluids and dousing the workbench, the adjacent walls, the floor and everything within a five-foot range with a finer coat of the same.  Some stray flecks of it even managed to hit the ceiling.  But whereas normally Mettablook would be extremely self-conscious about all of that, now they just sighed happily and detached from the body again, pulling the sensor pads off their soul and floating face to face with their new form - because they’d taken possession of this new and wonderful body as definitively and completely as ghostly possible.  “...I… t-think I’ll li-like you…  H-heh, heh…  I m-made a l-li-little bit o-of a mess…”, they said softly, looking at their new form, whose facial features had frozen into a perfect look of complete abandon, which was probably what their expression had been mid-orgasm, Mettablook considered with a guilty blush.  Then, they looked the body over and they gasped.  “ _O-oh n-n-no…!_ ”  Not only was the groin panel dented on the ground, but they’d apparently ridden their new body hard enough to cause one of the shoulder pads to detach, as well as overheating some circuitry inside of it, since smoke was oozing from the speaker at the front.  Undyne would have to repair those, and that would mean that the scientist would ask them how they’d damaged their body so much from a simple test run… and that was something she could _never_ tell doctor Undyne, _ever_ …

***

“...Mettablook?”

“Y-yes… doctor Un-und-d-dyne?”

“...Why… is there _glitter_ i-in your new body’s, uh, h-hip joint?  ...And, uh, on the i-inside of its… uh…”

“...”

“...W-when you say it was a good test drive…”

“ _...!  D-doctor Undyne…!!_ ”

“J-just checking, just checking… I’ll, uh, r-reinforce… s-some stuff…  a-and maybe install some, uh, extra filters?  For, uh, w-when you decide to… play with glitter again?”

“ _...nnnnnh…  L-le-let’s ju-just… get back t-to painting t-these…?  Pl-please?_ ”

“...Yeah, let’s.   _...Fuh huh heh…_ ”


	2. Private show

**Notes for the Chapter:**

> (dedicated to QueenNati/ask-mttblook and her fabulous fantastic cocopalm family of followers, of which I myself am a proud member! I just about killed her with teasers, this is my way of kinda-apologizing for that ;D I hope every single one of you cocopalm sinners (and others) enjoys this one, I had such fun writing it! Very dirty, but very very good)

“...mmm… metta, babe, you look so damn hot today… did ya shine those thighs just to get me to touch ‘em more? ‘cause you don’t have to make that much effort, i love runnin’ my hands all over you anyway...” They were laying in Mettablook’s bed, Papyrus with his hoodie off and his bony hand tangled in his botfriend’s life-like hair and Mettablook with his metallic arms wrapped securely around his bonefriend’s ribcage, his hands resting on Papyrus’ s shoulderblade on the left side and his clavicle on the right side. Mettablook giggled and winked at Papyrus before answering.

“I… l-love making the effort for y-you, Papyrus… Y-you’re _well worth_ t-the extra time spent p-polishing myself up f-for you…” He wanted to speak up again to get his bonefriend to kiss him, but it seemed Papyrus was again a step ahead of him: his supple silicone lips met Papyrus’ teeth in a loving yet passionate kiss, and a split second later Mettablook could feel Papyrus’ magic solidify into a tongue to tentatively trace his own metallic tongue, which channeled his magic as easily as always to make him feel every lightest twitch, flick and lave of Papyrus’ magic-fuelled appendage. “M-mmh… mmnn…”, the now-corporeal ghost groaned into the kiss, prompting Papyrus to detach just a little from him and speak teasingly.

“less talk, more enjoyin’ our time together… sans is stayin’ over in the capitol again so i’m off curfew for once, and i wanna make every second count, metta, babe…” Bony phalanges slid over Mettablook’s robotic body, magic following in their wake to soak into his metallic joints and the circuitry underneath, causing a shiver to run up them. “ahh, metta, babe… you’re so hot when you lean into my hands like that… and damn, your face… your expression… babe, you could make souls melt with just one wink…”

“T-the only soul t-that I want to me-melt is yours, Papyrus… s-sugarbones…”, Mettablook replied with a shy blush that belied the groan he let out the next moment at Papyrus’ unsubtle caress from his shoulder to his chest and then downward. “ _P-papyrus… mmmh…_ I-it feels so _nice_ w-when you… do that…”, he whispered, prompting a smug look from the tall skeleton.

“just ‘nice’, huh? not… amazing?” As he spoke, Papyrus very teasingly skirted the edge of Mettablook’s groin cover plate, a gesture the ghost had become very familiar with ever since he’d shown Papyrus his body. His bonefriend _worshipped_ his robotic form, to the point of borrowing animes from Alphys and deriving ideas from them: however, most of them turned out to be horrible, and they usually reverted back to their vanilla lovemaking - a thing that Mettablook found himself grateful for, if he was honest, because he felt apprehensive about _all_ of them. But there was one thing that hadn’t been horrible and worrying - something that was right up their alley, in fact, so Papyrus tried to indulge in it whenever he could and Mettablook didn’t want to stop him because of how wonderful it felt to get all worked up over his amazing bonefriend - and that was, surprisingly enough, plain teasing. Papyrus would touch his robotic body _just a little bit short of pleasurable_ and tell him to ask to be touched, or to share how he wanted Papyrus to take his soul and squeeze it in his hands until ectoplasm exploded from it, or sometimes he’d keep gently goading Mettablook into turning the tables on him by playfully whispering that he’d love nothing more than to be pinned down in the bed and _ravaged_ by Mettablook. Magic made for a surprisingly tight simulacrum of human bodyparts. That night, however, Papyrus seemed to go for something other than that. “...so… tell me, metta… what’s the _one thing_ ya did that felt _amazin’_ , huh? i mean, there’s gotta be something that felt like that once so ya know the difference…”, he said, lightly tracing the seam of Mettablook’s groin plate with his bony index finger, causing a melodious groan to escape the ghost.

“ _Ohh… P-papyrus…_ darlin’... t-there’s n-nothing…”, he tried while pushing his hips up, into the touch that felt so tantalizing, only for his skeletal boyfriend to chuckle and shake his head, trailing the finger up again and tracing it instead over the soul container.

“mmmnope, not buying that… c’mon, metta, babe… tell me… tell me what felt amazing so i can make you feel even better…” Mettablook’s metallic body flushed with a pink blush, indicative of his ghostly self within blushing, and then he spoke softly, pleadingly.

“I c-c-can’t tell you t-that… Mmm, please… _please, Papyrus… e-enough teasing…_ ”

“ooh, must be something _really_ kinky… metta, babe, didn’t know ya had it in ya-” Whether because his bonefriend suspected something or because he’d just genuinely stumbled on the right set of words, Mettablook wasn’t sure, but Papyrus’ words made him gasp and blush all the more, which of course _intensified_ his skeletal lover’s teasing. “oho… so it’s somethin’ bad enough to make you shine like a little lightbulb just _thinkin’_ about it… mmm, now i really got to know, metta… c’mon, babe… _enlighten me… and i’ll light you up, too…_ ” Groaning, Mettablook considered his options, and then, when Papyrus’ bony hand moved once again teasingly lightly to his hip and his groin-plate, he gave up resistance altogether, yearning too much for his bonefriend’s attentions.

“O-okay, I’ll t-te-tell you! J-just, please…”

“heh, okay… impatient, i get it…” Papyrus’ fingers were trained by now in finding the hidden latches that held his groin plate in place, and after a few seconds, he gently put it down on the ground beside the bed before wrapping one bony hand around Mettablook’s metallic member, stroking slowly. “...well, don’t stop talkin’ just yet…”, he said, grinning at the shuddering exhale that his motions drew from the ghost inhabiting the robotic body.

“O-okay… _ahh, y-yes…_ Mmm, Papyrus… d-darling… P-promise me y-you won’t… won’t… _ohh…_ promise y-you won’t be u-upset?”

“promise… now, what’s the _kinky_ li’l secret you have that’s makin’ you all flustered and _hot_ , metta, babe…”, Papyrus spoke lowly right into Mettablook’s robotic ear, prompting another unsubtle shudder from the ghost before he spoke in answer.

“I… w-when… when I t-te-tested this body… _oh m-my…_ I mmmay have… mmh… may have d-done more t-than just test… _nngh… P-papyrus, yes…_ I…” Papyrus didn’t stop stroking the robotic dick of his botfriend’s new body, but he slowed down just a notch again, causing Mettablook to softly whimper at the decrease in stimulation. The skeleton found himself carefully weighing his answers for once and decided to go with the mood from before, teasing and enticing.

“oh, so how exactly did you… _do more than just test_.. huh, metta, honey?”, he asked, to which Mettablook instantly flushed with a deep blush and a shy turn of his head so he looked instead at the pink wallpaper patterned with golden stars of varying size. But he did answer the question, and the words he spoke made Papyrus all the more resolved to see his teasing through to the end.

“ _Ahhh…_ I-I… U-undyne left me i-in the lab to… g-get a feel of mmmy new body… a-and I… fo-found t-these features, and… I w-wanted to know what i-it would f-feel like… to… t-to have s-sex the hu-human way… s-so I… t-tried touching m-my...s-sel...self- _oh, P-papyrus, please… a l-little faster…_ ”, the ghost pleaded, his entire robotic body shimmering with light pink energy as a result of arousal laced with the slightest discomfort at making such a confession. But when he looked at his bonefriend again, Papyrus grinned back at him, very deliberately letting go of his metal member but at the same time moving up for a deep, passionate kiss in which their tongues rubbed together so tightly that Mettablook found himself aching for his lover’s magic to wrap around him. “P-papyrus…”

“so you… played with yourself?”, the skeletal monster asked, prompting a nod from Mettablook - but that didn’t please his bonefriend, who answered with a light, _devilish_ note in his voice as he trailed his hands ineffectually over Mettablook’s shoulders. “nuh-uh-uh… _say_ it…”

“I p-played… with m-myself…”, Mettablook confessed, feeling about ready to burst out of his body again just so he could hide, but Papyrus at least moved his hand lower, bony fingers brushing over his waist and the soul container it held.

“...with the pads on your soul?” Mettablook nearly nodded again, but decided Papyrus’ touch, however he got it, was something he didn’t wish to give up just now, and he spoke his answer a second time instead.

“Mm, y-yes… a-and i-it felt so great, but t-touching i-isn’t sex so-” Mettablook halted mid-sentence in sudden shock. Did Papyrus’ touch mean so much to him, so much that he’d confess _the entire dirty little secret?_ Clearly his bonefriend was satisfied with the image of him just touching his own new robotic dick, so he could have left it at that. But he’d slipped up, and Mettablook could see the gears in Papyrus’ mind working at top speed considering the situation, leading to the inevitable conclusion.

“...oh… oh, heh heh heh heh… so you didn’t just _touch_ yourself, huh? you _fucked_ yourself… why, that’s _super kinky_ , metta…”

“Oh, d-don’t… don’t g-give me t-tha-that lo-look…!”, Mettablook whimpered, turning almost fully physically away from his lover in utter shame combined with the lightest, most delicate feeling of being turned on from just the memory. The feel of his new body _inside_ his ghost body… the double feedback he’d gotten from that… the way he’d basically abandoned all modesty because _it felt too good to be true…_ just thinking about it again made Mettablook’s magic glow all the more fiercely, illuminating his soul and casting pink, glittering sparkles all around his metallic body. Papyrus clearly noticed them, judging by his very light caresses that just barely brushed the tips of his finger over the base of Mettablook’s metal erection.

“mmm, looks like ya get all hot and bothered just remembering… must be _some experience_ …”

“O-oh… _y-yes,_ it was… _Mnnnn… P-papyrus, please… I… c-can you… touch me again…?_ I f-feel so… I _n-need_ you, s-sweetie… ohh, baby...”, the robot pleaded, but Papyrus shook his head, sitting up on the bed and leaning back against the wall, prompting Mettablook to groan in frustration. “P-papyrus… sugarbones, n-nooo… don’t l-leave me _aching…_ ”

“...y’know what, metta, babe? i think i need a li’l… _demonstration…_ of how you ‘tested’ that hot new body of yours…”, the skeleton said, grinning and folding his arms behind his skull, leaning back. His eyes never left Mettablook’s robotic body, though, roving his metallic form eagerly. Mettablook could almost _feel_ the path they followed, from his luscious hair down his chest and his soul container to his metallic dick that was now swollen with pent-up ectoplasm, and then back up to fix his eyes as he added: “...go on… show me how ya did it… ghost back out, keep those sensor pads on an’ _go for it, babe…_ ” He nearly purred out the last part, and Mettablook felt a wave of blazing heat sweep through him. A part - a _large_ part - of him was shy about putting himself on display for Papyrus, but that part was rapidly being silenced by the part of him that was hungry for stimulation and release, no matter how lewd and indecent it would get. After a few seconds’ hesitation, Mettablook opened the soul container and then pressed himself out of his metallic body, taking care not to dislodge the sensor pads from his soul as he did so.

“...O-okay… f-for you… Papyrus, darling…” Still, he felt apprehensive about putting himself on display like that, even for his bonefriend: last time he’d done that, he’d ended up breaking several critical internal parts of his new body because he hadn’t been able to hold himself back in the throes of his delight. But Mettablook told himself that it’d be okay with Papyrus there: surely his bonefriend wouldn’t allow him to actually damage his robotic body… not to mention his body was already semi-tangible and dripping at the prospect of having a repeat of his secret sin, at the request of his loving bonefriend even... He floated upward, settling his ghostly form down on his robotic dick slowly. “ _O-ohh… m-my… it f-feels… be-better than I r-remembered…”_ , he gasped, groaning as he felt the double pleasure of his body stretching and being filled alongside the joy of feeling his own body’s tight, slippery hold on his metallic member. “Oh, P-papyrus…”

“...tell me what ya feel, babe…”, Papyrus drawled out, pushing down his shorts so his pelvis was bared, his bony fingers caressing the upper ridges of the bone lazily as his eyes remained fixed on Mettablook’s form. “...ahh, metta, tell me what it feels like to you…”

“I-it feels… I feel… m-myself sl-slipping inside… i-its… _oh, mmmmh…_ so f-fulfilling… l-like… like… f-feeling myself b-being filled up… a-and filling up a-at the same time… ah… _y-ye-e-essss…_ ”, the ghost groaned, allowing himself to sink down all the way, his already soaking underside resting on the cool metallic exterior of his body, small glittering pink smears appearing all over its polished surface. “...ohh… i-it’s… so good… _ahh yessss…_ ”, he purred out, closing his eyes and lifting himself up just a little before sinking back down in a heartbeat, feeling Papyrus’ eyes drift lazily over him. Already, he could feel himself unable to hold back from riding his own body a little more forcefully than was strictly necessary. The electricity coursing through his soul was _amazing_ , comparable to the way Papyrus’ magic made him feel whenever they made love - and as such, it was no surprise that his bonefriend’s name spilled over his lips in a heated, lustful moan. “ _P-papyyyyyruuuuus…_ ”

“oh _damn, metta…_ ”, came the equally heated reply from Papyrus - opening his eyes a little, Mettablook saw his lover sitting with his eyes still trained on his form as he rapidly moved on top of his body, but his hands were busying themselves with caressing his bony form and his soul. “...f-fuck, I… forgot how _hot_ it sounds when ya _groan_ like that as a ghost… babe, s-say my name like that again…”

“ _P-papyrus… ahhh, d-darling… Papyruuus…_ d-do you like… mmmmh… m-me… riding my own b-body like this…?”, Mettablook asked, panting softly, resuming his motions with all of the added fervor his bonefriend’s pleas gave him. Papyrus’ only answer was a low moan, and Mettablook moaned as well, crooning softly and breathily into the heat that was quickly absorbing his lover as well as himself. “ _Mmmh, su-sugarbones…_ ohh, d-do you like… w-watching me… _e-enjoying myself_ …?”

“...god, metta… y-ya know i love this… you look so damn hot fuckin’ yourself…”, Papyrus ground out, unsubtly squeezing his soul in between his thumb and his index finger and gasping. “nnngh, _metta, b-babe…_ ”

“ _Ohh… n-no, Papyrus…_ d-don’t… oh, don’t… m-moan like that… t-this is already… already t-too much…!”, the ghost ground out, riding his metallic body as hard as ever before, causing the metallic joints to creak and the silicone face to shiver between its neutral, unpossessed expression and the appropriate joyful visage that matched the pleasure Mettablook felt. “I w-won’t… _agh, y-yes!_ I c-can’t last… l-long like this… oh, darling… your tea-teasing, y-your moans, the way you _look at me now_ … i-its too much, it’s… _ahh-ahhh…!_ ” Mettablook threw _all_ caution to the wind in favor of a steady, unrelenting rhythm of motion atop his own robotic body, driving himself down hard and fast and gasping in pleasure each time his metallic dick slid right into his oh-so-receptive spectral nethers that tightened in _all the right ways_ and that felt _so hot and welcoming_ … Ectoplasm was dripping from him, streaking his bedsheets and his robotic body with hot pink goop that evaporated increasingly more slowly, but the ghost didn’t notice and didn’t care. “Ohh! _P-papyrus… oh m-my…! I-I’m s-so… so…_ ” Mettablook barely even noticed Papyrus moving, or the skeleton’s magic solidifying, but when Papyrus knelt down over his metallic body’s upper legs, putting his hands on his ghostly, leaking form... “P-papyru- _uuuhhhh…!_ ” When his skeletal lover thrust into him with his magic having shaped itself into a perfect replica of the robotic member he was so enjoying himself, Mettablook’s surprised question turned into a heated cry. “ _O-Oh my g-g-g-go-ohhhh-d…!_ ”

“j-just- _nnh!_ \- enjoy t-this… m-metta- _ah!_ f-fuck, you’re s-so _tight_ , babe… s-so tight… mmmh! ...and so… _mmmh… g-god…_ ” Papyrus’ thrusts were slow and deep, just like everything about their lovemaking always was, but this time Mettablook felt how he held back - maybe it was the raw desire in him speaking, of course, the drive to run right into the fires of lust that putting on a show for his bonefriend had conjured up, but the ghost wanted nothing more than to feel Papyrus _let go_ just as he did, and would. So he pushed back against Papyrus’ motions, sinking the skeleton’s deep blue magic deep into himself and squeezing it against his robotic body’s dick eagerly, eliciting a shiver from his bonefriend. “ _s-shiiiit… h-how do ya… l-last? I w-would’ve… fuckin’... c-come by now… i-if I felt this good…_ ”, Papyrus uttered hoarsely, prompting Mettablook to speak hotly to the skeleton he’d come to give himself to more entirely than he’d ever thought possible.

“I… c-can’t… w-without you… oh, su-sugarbones, l-let go… g-go all out for mmme… _ohh, P-pa-papyrus… t-take me over…!_ ” Papyrus’ response was to grasp his semi-tangible form firmly and thrust into him hard and fast, his magic filling up Mettablook’s ghostly body and sinking deeper every time, while Mettablook was reduced to a whimpering, joy-wracked mess whose magic flared all around them, lighting up the walls like a pink strobe, flickering in time with the flutter of his soul… sparks of it hit Papyrus’ bones and he hissed in pleasure though his thrusts didn’t falter. Their mutual magic coiled outward, blossoming into great swirls of deep blue and vibrant pink, mingling into great blooms of purple that pulsed as if they were alive, and at the heart of it, the two monsters were racing towards oblivion hand in hand. Literally so, too: Mettablook’s ghostly hands had settled over Papyrus’, holding on for dear life while their souls were crackling with the pure energy they conjured together.

“m-metta… oh, metta, metta… s-shit, oh shit… oh god… n-not gonna h-hold out…”

“ _P-papyrus… ohhhh… ohh yes… yesssss…_ ” The tipping point was when Mettablook drove himself down _hard_ onto Papyrus, hard enough to sink his lover’s magic-fuelled erection all the way into himself and pressing it _hard_ into his glowing pink soul. “O-OHH _Y-YEEEEEESSSSSSS DARLING!!!_ ” The ghost didn’t tip over the edge so much as _dove_ over it, and as a result of his release, ectoplasm and magic exploded from his ghostly pink form. Papyrus, who sat hunched over Mettablook’s ghostly and metal bodies, got the full blast of it, which in turn set _him_ off.

“ _h-holy shiiiIIIIIIIIIIIIIIIiiit!!!!!_ ” Papyrus managed a good deep thrust into an already winding-down Mettablook’s body - and when his magic touched the ghost’s soul _again_ , Mettablook blacked out with a shriek…

 

“...metta… b-babe… you okay?”

“H-hhh… w-what… where… where am I? What h-happened…?” Mettablook sat up, his metallic joints protesting. Had he merely _dreamed_ about having used his robotic body as a tool for pleasuring himself again, in front of his bonefriend? But he’d been _outside_ of his body and now he was within it again, so… clearly that had to mean it _had_ been a dream, right? Opening his eyes wearily, he saw Papyrus sitting next to him, his bony hand resting gently in his own metallic one. ...Well, Papyrus _was_ naked, and there _was_ that deep blue glow in his chest that slowly died away, not to mention the scent of grapes and glitter hung heavy in the air, so maybe there was more to it than just a dream… “...Papyrus, I… are you okay?”

“heh, i’m _really_ great, honey… how are _you_ doin’?”

“...Well, I… suppose I’m…”, Mettablook said hesitantly, checking his inner displays for error messages but finding nothing. “...I’m d-doing… just fi-fine, as a matter of fact…”, he said softly, unable to keep himself from sounding surprised.

“all systems still good? nothin’ broken? soul back in place?”, his bonefriend persisted with a squeeze of his hand to accompany his question, worrying Mettablook.

“...P-papyrus, darling, are you… _s-sure_ you’re okay? I mean, you… look awfully startled… and why would my soul _not_ be in place?”, he tried, only for the skeleton to sigh shakily.

“...metta, you… i was worried, yeah.”, Papyrus admitted, wrapping an arm around Mettablook’s robotic shoulders and pulling him in for a gentle, loving kiss before continuing: “...you… don’t remember what happened, then?”

“No… w-why, did… Did my batteries run out in the middle of our passionate lovemaking session again?”, Mettaton asked - it was the only explanation he could come up with that made any kind of sense, despite having come round to the world again with no charge cable in sight. But Papyrus shook his head and, with a devious little grin, explained what had happened, causing a deep and instant blush to flash over Mettablook’s cool exterior like a wildfire.

“...nah, but close. you were gettin’ double-ended by me and your own hot body, babe, and… well, you came, set me off, and then… i dunno, ya just… _shrieked_ an’ _exploded_ with more magic and ectoplasm and then ya were… _gone_ , babe. i was, uh, kinda worried that i accidentally drove ya too far, ehehe…” Every word Papyrus spoke brought back the memory of another aspect that he’d forgotten: the raw pleasure, his release, Papyrus’ magic filling him up like no other time, and then the overwhelming sensation of his soul being touched _again_ while still sensitive and frazzled… Apparently, his lover had noticed his deep blush, because he added in a knowing tone: “...heh, looks like you remember after all, huh, babe? i’ve gotta say, now that i know what you losin’ it _twice in a row_ ends me up with-”

“ _Oh g-god…!_ ” If Mettablook had a way to make an entire metal body vanish from sight, he certainly would have used it right then and there, but as he didn’t have magic nearly powerful enough for that, he resorted to turning and burying his silicone face into one of his sequined throw pillows, which smelled like someone had sprayed hairspray all over it and which still marginally felt moist. How much ectoplasm had there even been?

“...hey… relax, metta, babe… i’m glad you enjoyed it that much…”, Papyrus spoke soothingly, gently turning Mettablook back around to face him: when the ghost looked at his bonefriend, he found Papyrus smiling down at him warmly, the lightest blush on his features only making him look more handsome. “...heh, i liked it too, babe. hard _not_ to like seeing you just _lose your shit_ -”

“P-papyrus…”, Mettablook whimpered, though he didn’t shy away again and he even managed a soft chuckle the next second. “...We-well, it was n-nice… t-telling you m-my little secret…”

“bet it was nice _showin’_ me your li’l secret, too… and man, was it ever hot… maybe we even gotta do that _more often-_ ”

“ _PAPYRUS!_ ”, Mettablook gasped out, the mere thought of behaving so indecently becoming a _regular feature_ in their love life too much to bear, though his bonefriend already raised his free hand in surrender.

“i’m not sayin’ ‘every other time’, just… maybe this shouldn’t be the last time we get to… go all out… promise i’ll be more careful with my magic next time, too. no more double-dippin’.”

“P-papyrus, _sugarbones, d-do-don’t sa-say it like t-that…_ ”, the robot groaned, though he had to concede the next second that he found the word highly appropriate: “...b-but yes, please, no more… ‘d-double-di-dipping’... I c-can handle only _so m-much_ at any t-time, darling…”

“even if it’s me?”, Papyrus questioned slyly, settling his bare bones against Mettablook’s metallic exterior comfortably, the warmth of his body radiating through the metal and silicone to send tiny waves of soothing energy to Mettablook’s soul, prompting him to lean closer and whisper out the answer.

“ _E-especially_ if it’s you, sugarbones.”


End file.
